Erasure-created bridge clash detection is incomplete

[smarter]

Same bug as SI-9912, this shouldn't compile:

class A {
  def compareTo(o: Any): Int = 0
}
class B extends A with Comparable[B] {
  def compareTo(b: B): Int = 0
}
object C {
  def main(args: Array[String]): Unit = {
    println(new B().compareTo(new Object()))
  }
}

... but it does and crash at runtime:

Exception in thread "main" java.lang.ClassCastException: java.lang.Object cannot be cast to B
        at B.compareTo(t9912.scala:5)
        at C$.main(t9912.scala:9)
        at C.main(t9912.scala)

[odersky]

Fixed by bridges changes, with error message cleaned up in #2372.